Psychologist and social scientist Dacher Keltner says the rich really are different, and not in a good way: Their life experience makes them less empathetic, less altruistic, and generally more selfish.

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In fact, he says, the philosophical battle over economics, taxes, debt ceilings and defaults that are now roiling the stock market is partly rooted in an upper class "ideology of self-interest."

“We have now done 12 separate studies measuring empathy in every way imaginable, social behavior in every way, and some work on compassion and it’s the same story,” he said. “Lower class people just show more empathy, more prosocial behavior, more compassion, no matter how you look at it.”

In an academic version of a Depression-era Frank Capra movie, Keltner and co-authors of an article called “Social Class as Culture: The Convergence of Resources and Rank in the Social Realm,” published this week in the journal Current Directions in Psychological Science, argue that “upper-class rank perceptions trigger a focus away from the context toward the self….”

In other words, rich people are more likely to think about themselves. “They think that economic success and political outcomes, and personal outcomes, have to do with individual behavior, a good work ethic,” said Keltner, a professor of psychology at the University of California, Berkeley.

Because the rich gloss over the ways family connections, money and education helped, they come to denigrate the role of government and vigorously oppose taxes to fund it.

“I will quote from the Tea Party hero Ayn Rand: “‘It is the morality of altruism that men have to reject,’” he said.

Whether or not Keltner is right, there certainly is a “let them cake” vibe in the air. Last week The New York Times reported on booming sales of luxury goods, with stores keeping waiting lists for $9,000 coats and the former chairman of Saks saying, “If a designer shoe goes up from $800 to $860, who notices?”

According to Gallup, Americans earning more than $90,000 per year continued to increase their consumer spending in July while middle- and lower-income Americans remained stalled, even as the upper classes argue that they can’t pay any more taxes. Meanwhile, the gap between the wealthiest and the rest of us continues to grow wider, with over 80 percent of the nation’s financial wealth controlled by about 20 percent of the people.

Unlike the rich, lower class people have to depend on others for survival, Keltner argued. So they learn “prosocial behaviors.” They read people better, empathize more with others, and they give more to those in need.

That’s the moral of Capra movies like “You Can’t Take It With You,” in which a plutocrat comes to learn the value of community and family. But Keltner, author of the book “Born To Be Good: The Science of A Meaningful Life,” doesn’t rely on sentiment to make his case.

In video recordings of conversations, rich people are more likely to appear distracted, checking cell phones, doodling, avoiding eye contact, while low-income people make eye contact and nod their heads more frequently signaling engagement.

In one test, for example, Keltner and other colleagues had 115 people play the “dictator game,” a standard trial of economic behavior. “Dictators” were paired with an unseen partner, given ten “points” that represented money, and told they could share as many or as few of the points with the partner as they desired. Lower-class participants gave more even after controlling for gender, age or ethnicity.

Keltner has also studied vagus nerve activation. The vagus nerve helps the brain record and respond to emotional inputs. When subjects are exposed to pictures of starving children, for example, their vagus nerve typically becomes more active as measured by electrodes on their chests and a sensor band around their waists. In recent tests, yet to be published, Keltner has found that those from lower-class backgrounds have more intense activation.

Other studies from other researchers have not produced the clear-cut results Keltner uses to advance his argument. In surveys of charitable giving, some show that low-income people give more, but other studies show the opposite.

“The research regarding income and helping behaviors has always been little bit mixed,” explained Meredith McGinley, a professor of psychology at Pittsburgh’s Chatham University.

Then there is the problem of Tea Partiers’ own class position. While they are funded by the wealthy, many do not identify themselves as wealthy (though there is dispute on the real demographics). Still, a strong allegiance to the American Dream can lead even regular folks to overestimate their own self-reliance in the same way as rich people.

As behavioral economist Mark Wilhelm of Indiana University-Purdue University Indianapolis pointed out, most people could quickly tell you how much they paid in taxes last year but few could put a dollar amount on how they benefited from government by, say, driving on interstate highways, taking drugs gleaned from federally funded medical research, or using inventions created by people educated in public schools.

There is one interesting piece of evidence showing that many rich people may not be selfish as much as willfully clueless, and therefore unable to make the cognitive link between need and resources. Last year, research at Duke and Harvard universities showed that regardless of political affiliation or income, Americans tended to think wealth distribution ought to be more equal.